Do you remember the "blood cleansing" problem that caused a stir in Japan in 2019? It was an incident where self-proclaimed influencers like blogger Hachū (Haruka Ito) spread beauty treatments with extremely little medical basis on SNS, leading to a backlash over "doubts about effectiveness" and "suspicion of exaggerated advertising." Now, more than six years later, a problem with a surprisingly similar structure is resurfacing in a far more dangerous form: the controversy surrounding "Mounjaro."
Mounjaro (generic name: Tirzepatide) is an injectable drug approved in Japan as a "treatment for type 2 diabetes." It is not a "diet drug." It is a medical drug of the type that is self-injected once a week and has a strong effect on blood sugar control. Because it also has the effect of suppressing appetite and reducing weight, it has spread rapidly on SNS as a "diet drug" in recent years. I want to emphasize this repeatedly: this is not a "diet drug."
The direct spark for the problem was a scene in the program "LAST CALL" released on YouTube in May 2026. This program, which has about 490,000 subscribers, features women aiming to become cabaret hostesses as "challengers," who are then judged by active top hostesses. In the program, Yuipisu, a hostess serving as a judge, lightly recommended to a challenger, "Why don't you try Mounjaro?" and shared her experience, saying, "When I first tried it, I lost 5kg in a month," and "Everyone can become like this." Furthermore, the program's MC, entrepreneur Yuji Mizoguchi, reported that he himself had invested in the online prescription service "diet beauty," which features Yuipisu as an ambassador. The service, which delivers Mounjaro with just a smartphone starting from 17,000 yen for the first time, was developed under the concept of "dieting without struggling alone."
Since Mr. Mizoguchi's circle has also caused controversy with the SANAE token case and the illegal online casino sponsorship problem in Breaking Down, it seems to be a regular occurrence for them to do troublesome things.
However, Mounjaro is neither a supplement nor a beauty serum. Much less is it a "diet drug." It is a prescription drug with a powerful blood-sugar-lowering effect, and using it for weight loss purposes is, in the first place, an "off-label use." In fact, an anti-obesity drug using the same active ingredient, "Zepbound," has already been approved in Japan, and if the purpose is obesity treatment, that should be used instead. Despite this, a specialist who has been involved in diabetes medical care for nearly 40 years flatly states that diverting Mounjaro for dieting is "nonsense and a violation of the law." And there is no end to cases where clinics and cosmetic surgery clinics involved in telemedicine prescribe it as a "diet drug" to women with a desire to be thin. There is also a strong suspicion of violating the Pharmaceuticals and Medical Devices Act.
Furthermore, it has been pointed out that if people who are already thin according to indices such as BMI use these drugs at their own discretion to suppress their appetite, parts that support basal metabolism, such as muscle, will wither, resulting in a major rebound.
Naturally, criticism of the program spread quickly. Dr. Mikito Chinen, a physician and novelist, pointed out on X that "Mounjaro is strictly a treatment for diabetes, and if used for dieting, it is an off-label use, and even if side effects occur, it is not covered by the relief system," and complained, "I would like amateurs not to recommend it so easily."
Yuipisu countered this on X, saying, "Must you be a doctor to be involved with pharmaceuticals?" but this only added fuel to the fire, and the backlash expanded further.
"The act of advertising the effects of pharmaceuticals as a personal experience" can itself conflict with the advertising regulations of the Pharmaceuticals and Medical Devices Act. Even if there is no malicious intent, emphasizing effects like "I lost 5kg in a month" or "You can become like this" regarding prescription drugs falls under expressions that the Medical Advertising Guidelines, in principle, prohibit. In fact, it's a direct out. Was there no decent adult around? The structure is such that responsibility can be questioned for the business operator, the advertising figurehead, and the platform, including Mr. Mizoguchi, who advertised the service within the program as an investor.
Administrative action has already begun. Of the 497 warnings issued by the Tokyo Metropolitan Government on X in fiscal 2025 regarding the illegal sale of pharmaceuticals, 375 cases, or about 75 percent, were related to transactions of diabetes drugs such as Mounjaro. The Metropolitan Government's Pharmaceutical Affairs Division issues warnings directly in the form of replies to posts and also requests X to delete them if they are not improved. Furthermore, cases where transactions are moving from X to Telegram have been confirmed, and the Metropolitan Government has now begun monitoring highly confidential communication apps. In addition, from January 2026, the Ministry of Health, Labour and Welfare has begun sending correction notices based on Article 68 of the Pharmaceuticals and Medical Devices Act to medical institutions that carry out inappropriate advertising, and if a violation is recognized, it will be subject to criminal penalties, including imprisonment for up to two years. I hope they will increasingly warn and crack down on these clinics that deceive fools.
The risk to the user themselves cannot be overlooked. This is not a "diet drug." In addition to serious side effects such as acute pancreatitis, cholecystitis, and renal dysfunction being reported, there is also the problem of drug interactions where the effect of low-dose pills and antibiotics is weakened due to the action of slowing stomach movement. Given the actual state of use in the nightlife industry, the impact on women taking pills for contraceptive purposes is particularly serious. And even if health damage occurs, off-label use is not covered by the Adverse Drug Reaction Relief System, and everything becomes self-responsibility. This point is not well known to many users.
What's even more troublesome is the aforementioned rebound after discontinuation. In a large-scale clinical trial overseas (SURMOUNT-4), it was reported that about 83 percent of patients regained weight one year after stopping Mounjaro, with more than half of the weight loss returning. Use started as a "diet drug" could lead to de facto long-term dependence, and the cost of late 10,000 yen to several tens of thousands of yen per month could continue semi-permanently. On SNS, posts fueling anxiety that "you'll get fat if you stop" are increasing, and the possibility that this itself causes dependence on Mounjaro cannot be denied, creating a vicious cycle that calls for new demand.
The victims who find it hardest to speak out in this problem are actually elsewhere. They are the type 2 diabetes patients who originally need Mounjaro. Due to the surge in off-label use for beauty and weight loss purposes, the supply of the drug has become tight, and the Ministry of Health, Labour and Welfare has repeatedly been forced to request medical institutions to "prioritize supply to type 2 diabetes patients who truly need it." The Japan Diabetes Society has expressed similar concerns. If blood sugar control breaks down, the risk of complications such as blindness, kidney failure, and nerve damage increases. The desire to "want to be thin" is hindering the acquisition of "medicine necessary to stay alive." This reality is hardly mentioned in the series of backlash reports. This is no different from the situation during the COVID-19 pandemic where fools flocked to the delusion that "Ivermectin works for the coronavirus," and as a result, Ivermectin became partially scarce, causing trouble for patients with strongyloidiasis and scabies who needed it as a treatment.
Looking back at "why this problem is repeated," a structural consistency with the blood cleansing scandal emerges. Influencers transmit their "experiences," SNS amplifies them, and administrative regulation falls behind. When criticism gathers, the parties involved claim they "just talked about their personal experience," and the news moves on to the next backlash case while substantial responsibility remains in limbo. According to research, the desire of young women to be thin is strongly influenced by information on SNS, and the internalization of the value that "being thin is desirable" is at the root of the problem. Experience-based advertising of pharmaceuticals through influencers is a business model that exploits exactly that internalization.
Blood cleansing was a "treatment with doubtful effects." No decent clinic would ever touch it, no matter how much money they could make. However, this time, Mounjaro is a real prescription drug, has real side effects, causes real supply shortages, and is suffering real patients in invisible places. Both the scale and the severity are incomparable to six years ago. Even so, if the structure of the problem has not changed, it is necessary to continue institutional discussions even after the backlash has subsided. Who is responsible and to what extent? What should the regulation of influencers be? How can we prevent the simplification of prescriptions through online medical treatment? To what extent should medical care be involved in the "slimming beauty" market? These are the questions that should be quietly re-asked precisely after the heat of the backlash has cooled.
